--- a/mozilla/tools/profiler/core/platform-linux.cc
+++ b/mozilla/tools/profiler/core/platform-linux.cc
@@ -38,6 +38,7 @@
 #include <sys/time.h>
 #include <sys/resource.h>
 #include <sys/syscall.h>
+#define gettid() syscall(SYS_gettid)
 #include <sys/types.h>
 #include <sys/prctl.h> // set name
 #include <stdlib.h>
